Apparatus for cleaning and descaling tubular elements



March 25, 1969 a R s ET AL 3,434,174

APPARATUS FOR CLEANING AND DESCALING TUBULAR ELEMENTS Filed March 24, 1967 Sheet 3 of 3 FIG. 3

United States Patent O Int. Cl. F28g 3/1; B08b 9/06, 7/04 U.S. Cl. lis-104.07 7 Claims ABSTRACT OF THE DISCLOSURE This invention is addressed to a device for cleaning the interior surfaces of tubular elements comprising a body member having a cylindrical section formed within the body member in which a piston is mounted for reciprocal movement having needle members extending outwardly from the opposite ends thereof for passage into and out of engagement with nozzles extending through the wall of the body and in which a source of supply of fluid under pressure communicates through a supply pipe to the opposite ends of the cylinder whereby displacement of the piston in one direction enables fluid under pressure to flow from the opposite nozzles to eflect rocking movement of the body to eTect a corresponding hammer blow onto the tubular element and whereby displacement of the piston in the opposite direction responsive to the fluid flow operates to close off the other nozzle and free the first to effect rocking movement of the body in the opposite direction for impacting the tubular element.

The present invention relates to an apparatus for cleaning and more particularly for descaling tubular elemerts.

It is well known to clean a tubular element such as a conduit for transporting a fluid, by means of a cleaning plug having an external diameter which is smaller than the internal diameter of the tube to be cleaned and which is advanced through the tubular conduit by the transported fluid. This device is suitable for deposits which are not very hard, such as parafl'ln, in the case of petrol conduits, and it has the disadvantage that the plug very frequently becomes blocked. This makes it necessary to provide a means for localizing the said plug and for opening the conduit with each blockage in order to free the plug.

It is also known to clean the tubes of the type described by means of a liquid jet at a pressure as high as is permitted by the tube. Once again, the strongly adhering deposits having a very high degree of hardness, such as crystalline scale, are resistant to the action of the liquid, even under pressures of the order of 500 bars.

The invention has -for its objects an apparatus `for cleaning and more particularly for descaling tubular elements and which overcomes the disadvantages heretofore experienced by eflecting the elimination of the most strongly adhering and hardest possible deposits.

These and other objects and advantages of this invention will hereinafter appear and for purposes of illustration, but not of limitation, embodiments of this invention are shown in the accompanying drawings in which FIG. 1 is an elevational view, partially in section, of the apparatus in LS simplest form;

FIG. 2 is a sectional elevational view showing a more developed example of the apparatus shown in FIG. 1;

FIG. 3 is a plan view of a hammer with two peens; and

FIG. 4 is a hammer having a multiple peen.

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The apparatus, according to the invention, comprises -an apparatus body, a cylinder within the body, a needle provided with a piston capable of being displaced in the cylinder, a supply pipe terminating by means of two conduits respectively at each end of the cylinder, two groups, each of which comprises at least one nozzle, placed on the side of the body, one of the groups being connected to the front end and the other to the rear end of the cylinder, each group being obstructed by the corresponding end of the needle when it is situated alongside the said group and, finally, a hammer fixed on the body in such a way that, when the apparatus is supplied and placed in a tube and when the needle is disposed at one end of the cylinder to obstruct the corresponding group of nozzles, the nozzles of the other group are supplied by the supply pipe, causing a movement by reaction of the body and the striking of a blow by the hammer against the wall of the tube. Thereafter, under the effect of the vacuum caused by the operation of the one group of nozzles, the needle is retracted to obstruct the group which has just discharged and free the other group for discharge, causing the retraction of the apparatus by reaction, so that a fresh blow is struck by the hammer on the wall of the tube opposite to the first blow, and so on.

According to a preferred constructional form of the apparatus, the small cylinder in which the needle is displaced is formed by the interior of a sleeve capable of sliding in the large cylinder formed in the body. In each of the positions outside its movement, the small cylinder Supplies the corresponding group of nozzles. The sleeve also carries a ring, which with the movement of the sleeve, is displaced in an enlarged portion of the large cylinder. The two parts defined by the ring are connected by a pipe provided with a needle valve to permit the adjustment of the rate of the blows struck on the walls of the tube.

The 'apparatus shown in FIG. 1 comprises a hammer 1 having two peens 11 and 12 With the hammer being fixed on the body 2 of the apparatus.

Formed inside the body 2 is a free cylindrical space 21 in which a needle 23 provided with a piston 233 is retained for reciprocal movement. One of the ends 211 of the free space 21 is connected firstly by way of a passage 241 to a nozzle 24 and secondly by a passage 261 to a pipe 26 for supplying fluid under pressure. Similarly, the other end 212 of the free space 21 is connected by way of a passage 251 to a nozzle 25 and by a passage 262 to the same pipe 26. The end 231 of the needle 23 is movable into and out of engagement with the inlet opening of the passage 241 to form a valve, the said valve being capable of closing the entry to the nozzle 24, while the end 232 of the needle forms a valve with the inlet end of the passage 251, said valve being adapted to obstruct the entry to the nozzle 25.

This apparatus is placed in the tube 3 which is to be cleaned and when it is supplied through the pipe 26 with fluid under pressure. When the valve formed by the end 231 of the needle 23 and the inlet end of the passage 241 is closed, fluid under pressure passes through the passage 261 and, finding the path free, passes by way of the passage 251 to the nozzle 25. By reaction to the jet emitted by the nozzle, the apparatus is displaced in the direction opposite to that of the said jet, so that the peen 11 of the hammer 1 strikes the adjacent wall of the tube 3.

In response to the movement of the fluid, a pressure drop is produced in the passage 262, while the passage 261 transmits fully the pressure existing at the supply pipe. Thus a pressure dilferential is established between the two ends of the piston 233 and the latter is retracted until the end 232 has obstructed the entry to the passage 251. The nozzle 25 is no longer being supplied with pressure fluid and the passage 241, 'from which the end 231 of the needle is disengaged, permits flow of pressure fluid to the nozzle 24. In reaction, the apparatus is forced back and the peen 12 of the hammer strikes the wall of the tube 3 facing it. A pressure diflerertial is again established between the ends 211 and 212, but in the opposite direction, so that the needle once shifts in position, and so on.

Each of the nozzles 24 and 25 can be replaced by several nozzles. Under such circumstances, it is advantageous for the nozzles of the group 24 and those of the group 25 to be symmertical in pairs relative to the axs 29.

The aXes of the nozzles can be perpendicular to the axs 29. The apparatus is then displaced by an auxiliary means, such as a winch. It is more advantageous to position the nozzles in such a way that their aXes meet the axs 29 at the same angle. The Component along the axs 29 of the reaction of the jets of the nozzles on the apparatus is then manifested by a thrust, which ensures the propulsion or axial movement of the apparatus in the conduit. Finally, it is possible to arrange the nozzles along axes which do not meet the axs 29. Under such circumstances, the apparatus is subjected to a rotational movement about the axs 29 in addition to the preceding axial movement.

The functioning of the apparatus is based on the pressure drop opposing the flow of the fluid in the passages 261 and 262. It is important, therefore, to form these passages with a small diameter or even to interpose therein constrictions 263 and 264, which are preferably adjustable and which can be formed by needle valves.

This very simple apparatus sometimes has the disadvantages in that the rate of reciprocatory movement of the needle is too fast and is adjustable only by the constrictions 263 and 264. Even when these latter are adjustable, the degree of adjustment itself is small.

The apparatus according to FIG. 2 is more complicated. It comprises a member permitting the separation between the supply pipe of one of the valves formed by one end of the needle and the passage giving access to the facing nozzle. The needle is thus able to slide only when this separating member is removed, `but this member which is subject to the same reduced pressure as the needle, has a brake that is adjustable within very wide limits.

This member is formed by a sleeve 22, in which the free internal space 211 forms a cylinder, referred to as the small cylinder in which the needle 23 is displaced. This sleeve slides in the cylinder 21 which is known as the large cylinder, formed inside the body 2. This large cylinder comprises an enlarged middle zone 213, in which is displaced a ring 222 fixed with the sleeve. In the middle Zone 213, is subdivided by the ring 222 into two parts 214 and 215 connected by 'a passage 216 equipped with an adjustable needle valve 217. This apparatus is placed inside a tube 3 and the pipe 26 is supplied with a fluid under pressure. It is assumed that initially the end 231 of the needle is in position to close the passage 241, and the space 211 is assumed to be isolatecl from the passage 261 by the sleeve and thus the needle does not move. However, the sleeve, subjected on the side of space 211 to the total pressure of the fluid in 26 and on the side of space 212 to this pressure reduced due to the pressure drop in the constriction 264 and in the passage 262, is displaced toward the space 212. This movement requires a part of the fluid present in the space 215 to pass into the space 214, but this passage is braked by the needle valve 217.

As soon as the sleeve has commenced its displacemcnt, thus opening the passage 261, the entire supply pressure is applied to the small piston 233 of the needle at the end 231, while the other end of this piston is only subjected to the same pressure reduced by the pressure drop in the construction 264 and the passage 262. The needle is thus forced back, and its end 232 will close the inlet to the passage 251 of the nozzle 25 to dscontinue the supply of pressure fluid and its jet is interrupted. On the other hand, the passage 241 of the nozzle 24 becomes free, so that this nozzle is supplied. In reaction, the body of the apparatus is pushed back and the peen 12 of the hammer strikes a blow against the wall of the tube 3. In the meantime, the sleeve 22 has continued its travel and has closed the passage 262. The nozzle 25 is then exactly in the position in which the nozzle 24 was initially disposed and the same phenomenon is reproduced in the reverse sense.

Thus, the reciprocatory movement of the needle is slowed down by the action of the sleeve. The oscillation frequency, that is to say, the frequency of the hammer blows, depends on the adjustment of the needle valves 263, 264 'and 217.

Attention is drawn to the fact that, for reasons of enabling the figure to be easily read, the sleeve has been shown with a length smaller than its real length. The end of the sleeve, the open end, is Situated substantially on the axis of the passage 262,

The hammer 1 has at least two peens 11 and 12 disposed symmetrically according to FIG. 3, but it may have more than two peens, in accordance with FIG. 4.

It will be observed that the needle is the only member of the a paratus subjected to the total supply pressure. The other members are only subjected to the diflerential pressure.

It will be understood that changes may be made in the Construction, arrangement and operation without departing from the spirit of the invention, especially as defined in the following claims.

We claim:

l. An apparatus for cleaning or descaling tubular elements comprising a body, a cylinder formed within said body, a piston having needle members extending outwardly from opposite ends and in which the piston is mounted for reciprocal movements within said cylinder, a supply pipe communicating through two conduits with the opposite ends of the cylinder, at least one nozzle extending through the body into communication with one end of the cylinder and at least another nozzle extending through the body in communication with the other end of the cylinder with the axes of the nozzles angled with respect to the direction of movement of the body and with respect to each other with the needles movable with said piston to open and close said nozzles, a source of pressure fluid in communication with the supply pipe whereby movement of the piston in one direction to bring the needle into engagement to close one of the nozzles enables fluid under pressure to flow from the other nozzle to rock the body in one direction and reversal of direction of movement of the piston to close the other nozzle and cause flow of pressure fluid to one nozzle for rocking movement of the body in the opposite direction, and a hammer fixed to the body for mpacting the tubular element in response to rocking movement of the body.

2. An apparatus as claimed in claim 1 which includes adjustable constrictions in the two conduits connecting the supply pipe respectively to each end of the cylinder.

3. An apparatus as claimed in claim 1 in which the cylinder in -which the needle is displaced is formed of a small cylinder in the form of a sleeve mounted for sliding movement in a large cylinder formed in the body so as to close, in each of its outer positions of movement, the supply of pressure fluid to the corresponding nozzles and a ring about said sleeve operable in an enlarged portion of the large cylinder to subdivide the enlarged portion into two sections, a passage connecting the two sections, a valve in said passage for adjustment of the flow of fluids through said passage between the two sections to adjust the rate of the blows struck on the wall of the tube.

4. An apparatus as claimed in claim 1 in which the axes of the nozzles are perpendicular to the axs of the til be to be cleaned.

5. An apparatus as claimed in claim 4 which includes means for displacement of the body axally within the tubular element.

6. An apparatus as claimed in claim 1 in which the aXes of the nozzles are at an angle smaller than the right angle of the axs of the tube to be cleaned whereby the component along the axes of the reaction jets from the nozzles propels the apparatus axially along the tube.

7. An apparatus as claimed in claim 1 in which the axis of at least one of the nozzles is angular to the axis of the tube to be cleaned.

References Cited UNITED STATES PATENTS EDWARD L. ROBERT, Pr'mary Exam'ner. 

